Medical support pads, e.g., a foam mattress pad for bedridden patients, must have certain properties. These pads must be sufficiently soft to reduce the formation of bed sores. The pads must have sufficient strength (e.g., tear and tensile) to permit handling, cleaning, and use in an institutional setting without tearing. More recently, these pads must also be flame retardant.
It has been conventional to use a variety of materials in an attempt to develop acceptable medical support pads of this type. For example, U.S. Pat. No. 3,689,948 to D. J. Groves et al. described the use of a polyvinyl alcohol gel support pad. Earlier, U.S. Pat. No. 3,451,071 to J. G. Whiteley described use of a pad containing polyether polyurethane (SEROFOAM brand).
In polyurethane foam technology, the desirable properties of good strength, acceptable softness, and flame retardance are not completely compatible in conventional technology. Polyether polyurethane foams, although usually giving soft and resilient foams, can have such desirable physical properties compromised if high loadings of solid flame retardants are needed. Recent attempts to develop commercial polyether polyurethane foams which might find utility as medical support (or "decubitus") pads have relied upon a higher content of solid filler additives than flame retardant additives. The presence of such solid filler materials cause an unacceptable degradation in the tensile/tear strength of the foam even though the foam is otherwise acceptable in regard to its fire retardance and softness.